A roller compactor is a well known densification and dry granulation machine for powdered material. The roller compactor produces uniform compacted sheets from powder, with consistent hardness and increased density. The roller compactor compacts powdered material between two rollers under pressure. The compacted powdered sheets can then be used for manufacturing free flowing granules for automatic packaging of products, compact granules for reduced product packing sizes, and granules for high speed tableting or encapsulation, with consistent dust-free purity and size.
In a conventional roller compactor machine, powder material is fed into a hopper and is pre-compacted with a screw feeder in the hopper. The screw feeder than delivers the powder to the rollers. The screw feeder normally is either a fully straight screw or a fully tapered screw, both of which have advantages and disadvantages. A fully straight screw enhances even distribution of the powder onto the compacting rollers. A fully tapered screw enhances pre-compaction and de-aeration of the powder within the hopper.
It is desirable to have a roller compactor machine having the benefits of both the straight screw and tapered screw.
Accordingly, a primary objective of the present invention is the provision of a roller compactor machine having an improved screw feeder.
Another objective of the present invention is the provision of a screw feeder for a roller compactor machine wherein the screw has both a tapered section and a straight section.
A further objective of the present invention is the provision of an improved screw feeder for a roller compactor machine wherein the screw has a tapered shaft and a straight shaft, with constant depth flighting on the shafts.
Still another objective of the present invention is the provision of an improved screw feeder for a roller compactor machine which is economical to manufacture, and durable and safe in use.
These and other objectives will become apparent from the following description of the invention.